Oscillator

ABSTRACT

An electronic timekeeping device includes bipolar integrated circuit implemented logic in combination with a liquid crystal display. A crystal controlled oscillator provides the system clock signal for controlling the logic of the electronic timekeeping device. The oscillator operates from a low voltage power source and provides a wide frequency tuning range.

United States Patent 9] in] 3,838,564 Holcomb Oct. 1, 1974 [5 OSCILLATOR 3,530,662 9 1970 Schoninger 58/23 R Inventor: Smnley w- Holcomb, Richardson 3,534,544 l0/l970 Oguey et al 58/23 A Tex. Primary Examiner-Edith Simmons Jackmon [73] Asslgnee g hjrstruments Incorporated Attorney, Agent, or Firml-larold Levine; Edward J. a Connors, Jr.; Stephen S. Sadacca [22] Filed: June 19, 1972 [21] Appl. No.: 263,919 ABSTRACT [52] U.S. Cl. 58/23 AC, 58/4 A, 58/5 1), An electronic timekeeping device includes bipolar in- 331/ 185 tegrated circuit implemented logic in combination [51] Int. CL... G04b 19/24, 604 3/()(), G04]; 19/30 with a liquid crystal display. A crystal controlled oscil- [58] Field of Search, 58/4 A, 23 R, 23 A, 23 AC, lator provides the system clock signal for controlling 58/23 BA, 50 R; 307/297; 331/185, 186 the logic of the electronic timekeeping device. The oscillator operates from a low voltage power source and [56] R f r Cit d provides a wide frequency tuning range.

UNITED STATES PATENTS 4 Claims, 48 Drawing Figures 3,518,458 6/1970 Camenzind 307/297 SUPPLY CURRENT REGULATOR FIG. 25 l6 5 l SEC. RESET 1 osc. EL S COUNTER 1- RESET FIGS. 6- FIG-5 6 9 HoURREsET 1-DATE RESET 30 CLOCK SYSTEM U 22 DECODE FIGS. 6-9

I DRIVER DISPLAY FIGS. 6-9

SU PPLY DC/DC CONVERTER FIG. 32

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' I DRIVER DISPLAY FIGS. 6-9 FI 3 P .DC/DC S 28 SUPPLY CONVERTER FIG. 32

mamww H914 sum 07 or 28;

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PAIENR at! new sum 10 ur za;

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PAIENIEIIIIEI I I 3.838.584

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1. A low voltage oscillator system for an electronic wristwatch comprising: a crystal controlled oscillator having complimentary transistors operating from constant current source means having a control element an with the output taken from emitter terminal of one of said complimentary transistors operating in an emitter/follower configuration and feedback to the control crystal taken from a collector terminal of the other of said complimentary transistors, and an output amplifier transistor of the same type as said other of said complimentary transistors operating from another constant current source.
 2. A loW voltage oscillator system as set forth in claim 1 including first bias stabilization diode feedback means coupling said collector terminal of said other transistor and the base terminal of said one transistor.
 3. A low voltage oscillator system as set forth in claim 2 including second bias stabilization feedback means coupling the output of said output amplifier transistor and the control source means of said constant current sources for said oscillator transistors.
 4. A low voltage oscillator system as set forth in claim 3 wherein said second bias stabilization feedback means includes a Schottky diode. 